Unipi and Touch Screens



  • hi,

    Do you Know if it is possible to use à TouchScreen with Unipi Board ? Is it possible to duplicate GPIO port in order to connect both Screen and Unipi ?

    Thanks.



  • hi,

    Do you Know if it is possible to use à TouchScreen with Unipi Board ? Is it possible to duplicate GPIO port in order to connect both Screen and Unipi ?

    Thanks.



  • Hello,

    it depends on what touchscreen are you using… We have good experience with simple hdmi screens with resistive touch foil connected to USB.



  • Hello,

    Thank you but HDMI touchscreen seems too expensive. I'm looking for a low cost touchscreen connected to GPIO only to monitor / control IO status on Unipi Board (Temperature, Relay status, … ).

    Sample : http://www.ebay.fr/itm/271723294953?ssP ... 1438.l2649

    It seems possible to duplicate GPIO port but I don't know if it is compatible with Unipi board.

    Thanks.



  • Hello,

    there is a conflict between the GPIOs used by UniPi and the display. But if you would need it, you could make a custom connector cable and use the GPIOs needed for the display and the rest for the UniPi. However you would loose some digital inputs which are directly connected to to GPIOs.. Check the UniPi documentation for more info on that.

    However if you make it work please share your project with us



  • Hi,

    The main problem with cheap GPIO based displays and touch screens is the RPi's limited capability to control SPI slaves. RPi has only two chip enable wire and the display and the touch screen use both. So if want to use an IO expander board (for example PiFace Digital 2) additonaly to the display and touch screen I can't do this because the expander board needs a chip enable wire too.
    So, the question is: does UniPi board use the SPI bus? Does it need a chip enable wire?
    Currenty I'm playing with TinyLCD's 3.5" TFT display which is a HAT of the Pi. It has additional GPIO connector given on TFT pcb to use rest pins for other use. It is possible to connect UniPi after this display if UniPi doesn't use the SPI bus.

    Ave, Saabi.



  • @saabi:1h6yk6kg:

    So, the question is: does UniPi board use the SPI bus? Does it need a chip enable wire?

    The UniPi itself does not use the SPI bus, however, with the provided cable the GPIOs 7,8,9,10,11 are used for reading the digital inputs I08, I09, I10, I12 and I07. So I believe it is possible to use the display but you will need a customized cable.